Larval Development of Dagetichthys Marginatus (Soleidae) Obtained from Hormone-Induced Spawning Under Artificial Rearing Conditions

SCIENTIA MARINA 71(3) September 2007, 421-428, Barcelona (Spain) ISSN: 0214-8358

Larval development of Dagetichthys marginatus (Soleidae) obtained from hormone-induced spawning under artificial rearing conditions

ERNST F. THOMPSON 1, NADINE A. STRYDOM 2 and THOMAS HECHT 1 1 Department of Ichthyology and Fisheries Science, Rhodes University, P.O. Box 94, Grahamstown, 6139, South Africa. E-mail: [email protected] or [email protected] 2 South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown, 6140, South Africa.

SUMMARY: Dagetichthys marginatus (formerly Synaptura marginata) larvae were laboratory-reared from wild caught adult broodstock as part of an aquaculture research project in temperate South Africa. A larval description for the species is provided in this paper. This work also represents the first larval description for the genus Dagetichthys, which is represent- ed by five species, three of which occur in the western Indian Ocean. Larval development in D. marginatus is typical of Soleidae. Dagetichthys marginatus larvae are heavily pigmented, with four characteristic melanophore “blotches” on the finfold. These larvae are easily distinguished from other soleid larvae commonly encountered in temperate South Africa based on the large size at flexion (5-7.06 mm BL) and the heavily pigmented body. Laboratory-reared postflexion larvae in this study showed similar meristic counts to those of wild caught adult fish. Despite the common occurrence of mature adults of this species in shallow marine waters off temperate South Africa, larvae are absent from nearshore ichthyoplankton catches. As yet, the spawning strategy of the species is unknown. Keywords: Synaptura, fish larvae, description, temperate ichthyoplankton, soleids, aquaculture.

RESUMEN: DESARROLLO LARVARIO DE DAGETICHTHYS MARGINATUS (FAMILIA: SOLEIDAE) A PARTIR DE PUESTA INDUCIDA POR HORMONAS EN CONDICIONES DE CULTIVO ARTIFICIALES. – Las larvas de Dagetichthys marginatus (anteriormente Synaptura marginata) se cultivaron en el laboratorio a partir de adultos capturados en el medio natural como parte de un proyecto de investigación en la zona templada de Sudáfrica. En este trabajo se presenta la descripción de las larvas de esta especie. Este trabajo también representa la primera descripción del Dagetichthys, representado por cinco especies, tres de las cuales se encuentran en el Oeste del Océano Índico. El desarrollo larvario de D. marginatus es el típico de la familia Soleidae. Las larvas de Dagetichthys marginatus están fuertemente pigmentadas con cuatro característicos bloques de melanóforos en la aleta primordial. Estas larvas se distinguen fácilmente de otras larvas de soleidos comúnmente encontradas en la zona templada de Sudáfrica en base a su gran longitud en el estadio de flexión (5-7.06 mm BL) y a su cuerpo fuertemente pigmentado. Las larvas en estado de postflexión obtenidas en el presente cultivo mostraron similares contajes que los adultos capturados en el medio natural. A pesar de la común aparición, en aguas someras, de adultos maduros de esta especie frente a la zona templada de Sudáfrica, las larvas estuvieron ausentes en las muestras de ictioplanton recolectadas en dicha zona. Hasta el momento, la estrategia de puesta de esta especie es desconocida. Palabras clave: Synaptura, larvas de peces, descripción, ictioplancton de zonas templadas, soleidos, acuicultura.

INTRODUCTION life history strategy (fecundity, maturity, egg size, inter alia), good natural growth rates and an The white-margined sole, Dagetichthys mar- established, lucrative market for flatfish ginatus, was identified as a suitable candidate (Thompson, 2004). Wild broodstock were suc- species for aquaculture in South Africa, based on cessfully induced to spawn and the larvae were 422 • E.F. THOMPSON et al. reared through to metamorphosis under controlled Nothing is known about the early life history of laboratory conditions. this species prior to the allocation of this species to Dagetichthys marginatus (Boulenger, 1900), for- the genus Dagetichthys. An isolated report on egg merly Synaptura marginata (Vachon et. al., in size (2.08 mm) (Ochiai, 1966) was shown to be inac- press), is one of 56 flatfish species that occur in curate due to the misidentification of adult fish southern African waters, 16 of which are soleids (Vachon et. al., in press), while a record of three D. (Smith and Heemstra, 1986). The new soleid genus marginatus larvae (2.8-3.2 mm) (Beckley, 1986) in Dagetichthys consists of five species, three occur- temperate South Africa remains unconfirmed. The ring in the western Indian Ocean (Vachon et. al., in only information for larvae of the 14 species in the press), namely D. marginatus, D. albomaculatus genus Synaptura (Eschmeyer, 1998) was an isolated (Kaup, 1858) and D. commersonnii (Lacepède, description for Synaptura kleinii (Brownell, 1979), 1802). The distribution of Dagetichthys marginatus which was subsequently moved to the genus is listed by Heemstra and Gon (1986) as extending Synapturichthys (Heemstra and Gon, 1986). Hence from the Mozambique Channel southwards to there are no published larval descriptions for the Durban on the east coast of South Africa. However, new genus Dagetichthys. Thompson (2004) recorded the distribution of D. Laboratory rearing of D. marginatus for aqua- marginatus to extend into temperate waters as far culture provided an ideal opportunity to study and south as Gansbaai (34°35´S, 19°20´E), where it is describe larval development. Understanding the the most abundant shallow water sole species on critical changes in morphology and behaviour of intertidal and sub-tidal sandbanks. this species, as well as the timing and duration of

TABLE 1. – Meristic, morphological and pigmentation (melanophore) information on soleid species occurring in South African waters for which larval descriptions are available (* denotes size at completion of flexion, while the others are size at commencement of flexion). Information provided is taken directly from literature cited (adapted from Wood, 2000).

Species Myomeres (range for Vertebrae Size at Pigment Reference preflexion and flexion) flexion (mm)

Austroglossus microlepis 56-58 55-57 5.2-5.5 Dorsal and ventral midline; gut; O’Toole, 1977; lower jaw; behind eyes; pectoral fins Brownell, 1979 Austroglossus pectoralis 50-58 (8-10 + 40-49) 58 3.5-3.8 Dorsal and ventral midline; fore- and Wood, 2000 hind-brain; snout; lower jaw; ventral and lateral gut; small spots on finfold Dicologossa cuneata 44-47 (9 + 35-38) 43-45 6.3-6.5 Dorsal and ventral midline; midbrain; Lagardère and hindbrain; finfold; swim bladder, Aboussouan, 1981 gut; head Heteromycteris capensis 39-41 (10 + 29-31) 40-43 6.2* Midline body contour; Three spots on Brownell, 1979 ventral finfold; ventral gut wall; lower pectoral fin margin

Monochirus lutens 36-38 36-40 5 Dorsal and ventral midline; midbrain; Nichols, 1976 in posterior tail (early); finfold; ventral Olivar and Fortuño, abdominal wall 1991 Monochirus ocellatus 34-37 (8-9 + 26-28) 37-38 4 Three dorsal and two ventral concen- Palomera and Rubies, trations of small spots on finfold; caudal 1971 in Olivar and tip; dorsal and ventral body contour Fortuño, 1991 Pegusa lascaris 47 (9 + 38) 42-47 5.3 Many small melanophores scattered over Clarke, 1914 in head, body and fins. Heaviest concen Ahlstrom et al., 1984; trations over lateral and ventral gut Russell, 1976 surface and laterally on tail Synapturichthys kleini 42-45 (9-10 + 33-35) 46-47 6.5* Densely packed stellate melanophores Brownell, 1979 scattered over all body surfaces and finfold Dagetichthys marginatus 40 (preflexion) 42 5-7.6 Three distinct clusters on the dorsal and This study one on the ventral finfold and later on fins, when the last dorsal and ventral cluster fuses to form a band over the body

SCI. MAR., 71(3), September 2007, 421-428. ISSN: 0214-8358 LARVAL DEVELOPMENT OF DAGETICHTHYS MARGINATUS • 423 each of these events, will facilitate larval rearing Although three successful larval batches were protocols. reared, larvae from only one spawning were used to Larval descriptions for coastal fishes are general- avoid differences in broodstock condition and thus ly lacking in South Africa (Strydom and Neira, in egg quality, which affect larval development press). Descriptions are, however, available for eight (Bromage, 1995). Ten larvae were collected at spe- of the 16 soleid species occurring on the South cific intervals representing developmental endpoints African coast (Table 1). This paper presents the first after hatching. All samples were fixed in 5% description of the early larval development of the buffered formaldehyde for 24 h and then transferred white-margined sole, D. marginatus (Boulenger, into 70% ethanol. Representatives of the larvae 1900). This information will assist in the identifica- examined and described in this paper were lodged in tion of this species in ichthyoplankton samples and the national fish collection at the South African in so doing provide much-needed information on its Institute of Aquatic Biodiversity (SAIAB 77531). spawning and its larval and juvenile distribution in All terminology pertaining to larval fishes fol- coastal waters off South Africa. lows that of Neira et al. (1998). The term “larva” was used to designate all stages in the early life history from hatching to the attainment of a full fin ray MATERIALS AND METHODS complement, squamation and the subsequent loss of all larval characters, at which stage the “larva” All broodstock fish were identified as becomes a “juvenile”. Settlement stages still in pos- Dagetichthys marginatus based on meristic counts session of isolated larval characters and in a plank- given in Heemstra and Gon (1986) and Vachon et. tonic state were considered as larvae. Newly settled al. (in press). Male and female fish were collected individuals were called “early juveniles” and were with a hand-held, multiprong spear between Port included in the study. The term “larva” was further Elizabeth (33º57’S; 25º38’E) and Great Fish River subdivided into yolk-sac, preflexion, flexion and Point (33º31’S; 27º06’E) during the spawning sea- postflexion stages. The following body measure- son (October to March) (Thompson, 2004) and ments were made for all developmental stages: body transported to the marine hatchery at Rhodes depth (BD), body length (BL), eye diameter (ED), University, Grahamstown. Females were induced to head length (HL) and pre-anal length (PAL). All ovulate using Aquaspawn®, a GnRH analogue measurements were made according to Neira et al. (Millar’s Clinical Laboratories, Touws River, South (1998) to the nearest 0.01 mm using a Leica dissect- Africa) at a dosage of 0.5 ml per kg of body weight. ing microscope fitted with an eyepiece micrometer Eggs were obtained by strip-spawning the females for larvae <10 mm and Vernier calipers for larger approximately 38 h after the single hormone injec- specimens. Body length (BL) represents notochord tion. Males were sacrificed and the testes were length in preflexion and flexion stage larvae, and homogenized in a small volume (1 ml) of saline standard length in postflexion larvae and early juve- solution (0.9 ppt). Eggs were fertilized with the tes- niles. All proportional values are a proportion of BL ticular homogenate. After fertilisation and harden- unless otherwise noted. ing, eggs were thoroughly washed with seawater and divided among six 60 L black upwelling incubators at a density of 20 eggs/L for egg incubation and lar- RESULTS val rearing. Hatching occurred between 42 and 49 h after fertilisation and exogenous feeding began three Age and size range of developmental stages days after hatching (dah). Larvae were fed twice daily on newly hatched brine shrimp, Artemia salina A total of 104 laboratory-reared larvae (2.09- nauplii, from first feeding to 16 dah. After this, lar- 14.75 mm BL) were examined to describe morpho- vae were fed two-day old, Super Selco (INVE) metrics, meristics and pigmentation. Newly hatched enriched A. salina. A new batch of enriched nauplii larvae (0 h) ranged in size between 2.09 and 2.19 was provided every 24 h at a density of five individ- mm BL. The yolk-sac was completely absorbed uals/ml. Temperature and salinity were kept constant after 4 days, while the oil globules persisted for at 19 ± 0.8°C and 35 ppt, respectively, for the dura- approximately 12 hours. Yolk-sac larvae ranged tion of egg incubation and larval rearing. from 2.09 to 3.41 mm BL (Table 2). The preflexion

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TABLE 2. – Body length and body proportions of the larval and settlement stages of Dagetichthys marginatus reared under laboratory conditions (n, number of larvae; BL, body length; HL, head length; BD, body depth; PAL, preanal length; SD, standard deviation).

Yolk-sac Preflexion Flexion Postflexion Settlement n403020104

BL Range 2.09 – 3.41 3.44-5.15 5.00-7.06 9.50-11.60 13.50-14.75 Average 2.79 4.04 5.96 10.59 14.03 SD 0.50 0.48 0.70 0.57 0.58 HL (%BL) Range 12.35-17.14 17.86-25.23 22.02-28.04 25.47-30.77 26.32-31.19 Average 14.63 21.17 24.50 27.95 28.99 SD 1.12 2.04 1.45 1.80 2.04 ED (%HL) Range 35.29-70.00 28.57-45.00 21.67-30.43 15.63-23.21 14.71-16.67 Average 52.74 35.91 25.92 19.34 15.43 SD 9.95 3.66 2.25 1.94 0.93 BD (%BL) Range 10.09-19.12 22.22-34.23 28.44-36.28 39.62-50.00 30.70-33.05 Average 13.61 26.59 31.65 44.99 32.30 SD 3.02 3.28 1.96 3.73 1.10 PAL (%BL) Range 42.20-62.69 40.00-48.65 42.59-49.56 32.76-46.32 22.88-25.93 Average 51.54 43.52 46.60 39.65 24.53 SD 6.84 2.55 1.89 4.03 1.26 stage lasted for 6 days after yolk-sac absorption. to short (mean PAL 24.53%) at the settlement stage During the preflexion stage the larvae ranged from (Table 2). 3.44 to 5.15 mm BL. Flexion of the notochord tip Newly hatched larvae have a moderate to large, started 11 dah and was completed between 20 and unsegmented yolk-sac (0.50-0.59 mm diameter). In 30 dah. Flexion stage larvae ranged from 5.00 mm excess of 50 oil globules are distributed in the yolk- (11 dah) to 7.06 mm BL (15 dah). The smallest post- sac and are clustered together in groups of eight or flexion larva measured 9.50 mm BL at 30 dah. less situated at the posterior end of the yolk-sac. An additional dense cluster of about 30 oil globules is General morphology also situated at the posterior end of the yolk-sac. Prior to first feeding, the oil globules fuse to form Larvae are elongate (Fig. 1A) in body shape dur- one large globule situated in a posterior-dorsal posi- ing the yolk sac stage (mean BD = 13.61%), becom- tion in the reduced yolk-sac. The eyes are unpig- ing more moderate (Fig. 1B) at the preflexion stage mented in yolk-sac larvae and become fully pig- (mean BD = 26.59%). Body depth increases from mented and functional in early preflexion larvae by the onset of flexion as the gut enlarges and coils 3.44 mm. The mouth becomes functional at the prior to the settlement stage. Larvae remain moder- same time as the gut is fully formed in preflexion ately deep-bodied until metamorphosis into juve- larvae at 3 dah (3.44 mm BL) and larvae start feed- niles (BD 28.44-50.00%). The head is compressed ing on Artemia salina 4 dah. Two to five small villi- and small during the yolk-sac stage (HL 14.63%), form teeth were first observed at 16 dah (6.60 ± 0.27 becoming moderate in size during later develop- mm BL) on the blind and ocular side of the dentary. mental stages (HL 21.17-28.99%). The snout is Villiform teeth are present on the premaxilla at 31 short, giving the head a rounded, convex dorsal pro- dah, while the number of teeth on the blind side den- file during preflexion and flexion (Fig. 1). A dorsal tary increases. At this stage, the teeth on the ocular hump forms during the postflexion stage. This very side dentary disappear. No further teeth develop on distinct fleshy extension protrudes over the anterior, the ocular side premaxilla at any stage during devel- dorsal surface of the head and joins with the dorsal opment (Ende, in prep.). Preflexion larvae have a fin (Fig. 1D). The head and snout profile becomes myomere count of 40, while the vertebral count is 42 convex after eye migration is complete. Both body after ossification. Myomeres could not be counted depth and head length increase proportional to BD during any other larval stage due to heavy pigmen- during development. Pre-anal length gradually tation. The air bladder is visible in isolated larvae 7 decreases throughout development, from long to dah and not in older larvae due to heavy pigmenta- moderate (PAL 62.69-32.76%) during early stages tion. Larvae are, however, positively buoyant until

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FIG. 1. – Larvae of laboratory-reared Dagetichthys marginatus. (A) newly hatched yolk-sac stage (myomeres, although present, were too indistinct to draw accurately). (B) preflexion. (C) flexion. (D) postflexion. flexion, after which they become substratum-associ- Development of fins ated. This indicates the presence and use of an air bladder during the early stages of larval develop- Pectoral fin buds appear in late yolk-sac or early ment. The gill membrane is also free from the isth- preflexion larvae from 3.03 mm BL. These increase mus at this stage. No head spination is present at any in size throughout development up to settlement stage of development. (13.52 mm BL), when the fins decrease in size and

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FIG. 2. – Settlement stage larva of Dagetichthys marginatus (10.53 mm BL) reared under laboratory conditions. seven pectoral-fin rays develop on both the ocular 4 dah and are replaced by branched, stellate and blind sides. Paired pelvic-fin buds start develop- melanophores. ing during the late flexion stage from 6.50 mm BL (15 dah) and are fully developed in early settlement Head pigmentation stage larvae from 13.52 mm BL, with 3 rays present. The dorsal, caudal and anal-fin anlagen appear Head pigmentation is characterised by simultaneously in late preflexion larvae by 4.72 mm melanophores on the lower lip (extending along the BL. Incipient rays form during early flexion and a lower jaw line in later stages), preopercle, behind the full adult ray complement (D 70, A 55, C18) is pres- eye and the isthmus in preflexion larvae, increasing ent by late flexion stages from 6.13 mm BL (15 in number and intensity in flexion larvae. In some dah). The dorsal, caudal and anal fin membranes flexion specimens, a melanophore ring appears remain fused throughout development and in adults. around the eye. Postflexion larvae lose this general No fin spines or extraordinary rays are present in pattern of pigmentation, as the whole head region Dagetichthys marginatus larvae during any stage of becomes covered with many random melanophores. development. An isolated group of internal melanophores is visible at the join of the lower and upper jaw, as well as General pigmentation pattern during on the dorsal hump of the head in preflexion larvae. development Trunk and tail pigmentation Pigmentation increases from sparsely pigmented yolk-sac larvae to heavily pigmented settlement Trunk pigmentation in early preflexion larvae stage larvae. The general pattern of occurrence of consists of three large clusters of melanophores or melanophores on the head and trunk remains similar “blotches” on the dorsal finfold and one on the ven- from first feeding (3 dah) to postflexion larvae, tral finfold (Fig. 1B). The first of the dorsal blotch- although intensity and melanophore type (e.g. punc- es is situated anterior to the nape, the second occurs tate and/or stellate) increase with development (Fig. opposite the anal opening (midway down the trunk) 1). Distinctive melanophores are described in the and the third occurs two thirds along the length of text but the body of the larva is also covered with the trunk. The ventral blotch is in line with the third very small punctuate melanophores that are random- dorsal blotch. This third dorsal and the ventral ly distributed in the areas as shown in Figure 1. blotch expand laterally over the trunk, across the Xanthophores (not indicated in Fig. 1 as these dis- myomeres, until the two fuse and become an “hour- appear in preserved specimens) dominate the pig- glass shaped” band across the larva during late pre- mentation of live yolk-sac larvae, mirroring the flexion. This band widens during flexion to form melanophore pattern observed in four-day-old lar- one solid band and continues to be visible as a vae. Xanthophores, however, decrease in number “dusky bar” in postflexion larvae. The first two dor- and intensity until they disappear completely around sal blotches remain visible during and after fin ray

SCI. MAR., 71(3), September 2007, 421-428. ISSN: 0214-8358 LARVAL DEVELOPMENT OF DAGETICHTHYS MARGINATUS • 427 development. In live larvae, iridiophores overlay the partially controlled by environmental conditions, melanophore pattern of the three dorsal blotches at such as vertebral and fin ray counts (Hunter 1984). the start of flexion and continue to exist until the end In this study, however, fin ray and vertebral counts of flexion. The notochord, during preflexion, is observed in laboratory-reared larvae fell within the sparsely pigmented with punctuate melanophores range for wild-caught adult Dagetichthys margina- that become heavily stellate during flexion, covering tus; D 70-81, A 55-64, P 7, C 18, V 42-45 (Vachon almost the entire thickening of the myomeres. With et. al., in press). this thickening during flexion, internal pigmentation Dagetichthys marginatus larvae are easily distin- appears on the ventral side along the notochord and guished from other pleuronectiform larvae common- above the gut, and become increasingly difficult to ly found in temperate nearshore waters of South see as the external pigmentation develops. The gut is Africa. The larvae of the cynoglossid, Cynoglossus even, but lightly pigmented in preflexion larvae. capensis (Brownell, 1979) are easily distinguishable This pigmentation pattern remains the same from those of D. marginatus by four elongated ante- although individual melanophores expand and the rior dorsal rays that only start disappearing in late pigmentation becomes heavy, concealing any inter- postflexion stages. At this stage C. capensis is a left- nal pigmentation that might be present in and around eyed (sinistral) flatfish, while D. marginatus is right- the gut during flexion and later stages of the devel- eyed (dextral). Similarly, Cynoglossus zanzibarensis opment. Pelvic fins become pigmented with (Wood, 2003) can be distinguished from D. mar- melanophores during the postflexion stage and ginatus by two elongated anterior dorsal fin rays up remain so through to the juvenile stage. The base of to flexion, after which it becomes a sinistral flatfish. the pectoral fin becomes pigmented during preflex- Other characteristics that could be used to make a ion stages. distinction between Cynoglossidae and D. margina- A cluster of melanophores appears on and tus are the higher meristic counts, a coiled gut and a around the notochord, anterior to the tip, during the single pelvic fin (Leis and Carson-Ewart, 2000). preflexion stage and disappears at the end of flexion. Except for Arnoglossus capensis and Other than this cluster, the caudal peduncle and cau- Pseudorhombus arsius, bothid larvae are not com- dal fin remains free of melanophores. monly found in ichthyoplankton samples in temperate coastal waters of South Africa (Strydom, unpublished data). The larvae of A. capensis have been DISCUSSION partially described by Brownell (1979). Despite the paucity of descriptive information, D. marginatus Dagetichthys marginatus larvae follow the typi- can be distinguished from bothids by the presence of cal pattern of soleid development (Leis and Trnski, a continuous dorsal, caudal and anal fin membrane 2000). Fin development as well as the lack of that remains fused until the fin rays ossify. Other extraordinary long rays and spines is characteristic. notable bothid characteristics are the elongated dor- The anterior dorsal fin supports (pterygiophores and sal fin rays during early larval stages and the fact the proximal portion of rays) form a deep notch with that they are sinistral flatfish. the top of the snout and head of postflexion larvae. Soleids commonly encountered in temperate The eye migrates through this notch and the notch inshore waters of South Africa are Heteromycteris closes following eye migration. This anterior exten- capensis, Solea turbynei (formerly S. bleekeri) and sion of the dorsal hump on the head is, however, not Austroglossus pectoralis (Table 1). The larvae of A. common among soleids. The only other described pectoralis and S. turbynei are notably smaller than larval soleid with a similar morphological feature is those of D. marginatus, reaching flexion at a size of Heteromycteris japonicus (Ahlstrom et al., 1984). 3.5-3.8 mm (Wood, 2000) and ~3.5-3.9 mm All the larvae used for this description were lab- (Strydom, unpublished data.), respectively, whereas oratory-reared from eggs, which according to D. marginatus range from 5 to 7.06 mm BL at flex- Watson (1982) may result in heavier pigmentation. ion. A. pectoralis and H. capensis larvae are light to Laboratory reared larvae may also show slightly dif- moderately pigmented, S. turbynei larvae are mod- ferent meristic characteristics to those of wild- erate to heavily pigmented and D. marginatus larvae caught individuals. Variable laboratory rearing con- are heavily pigmented. Postflexion larvae of all ditions can manifest in those characteristics that are these species can also be separated by fin ray counts.

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of Sciences, San Francisco. Axcess updated internet site 17 Dagetichthys marginatus can also be separated from April 2006. H. capensis by the presence of the fused anal, cau- Heemstra, P.C. and O. Gon. – 1986. Family No. 262: Solidae. In: M.M. Smith and P.C. Heemstra (eds.), Smiths’ Sea Fishes. dal and dorsal fins. Synapturichthys kleini Southern Book Publishers, Johannesburg. (Brownell, 1979) has a very different melanophore Hunter, J.R. – 1984. Synopsis of culture methods for marine fish larvae. In: H.G. Moser, W.J. Richards, D.M. Cohen, M.P. arrangement to D. marginatus, although fin ray Fahay, A.W. Kendall Jr and S.L. Richardson (eds), Ontogeny counts and sizes at different developmental stages and Systematics of Fishes. Am. Soc. Ichthyol. Herpetol., Spec. Publ., 1: 24-27. are similar. Synapturichthys kleini has densely Lagardère, F. and A. Aboussouan. – 1981. Développement du packed stellate melanophores scattered randomly céteau, Dicologoglossa cuneata (Moreau, 1881) (Pisces, Pleuronectiformes, Soleidae): II. – Description des larves, over the body and finfold, while D. marginatus has Cybium, 5(2): 53-72. a distinctive melanophore pattern with four charac- Lasiak, T.A. – 1983. Recruitment and growth patterns of juvenile marine teleosts caught at King’s Beach, Algoa Bay. S. Afr. J. teristic melanophore blotches on the finfold. Zool., 18(1): 25-30. The actual spawning habitat of D. marginatus Lasiak, T.A. – 1984. Structural aspects of the surf-zone fish assem- blages at King’s Beach, Algoa Bay, South Africa: Long-term has not been identified, mainly due to the lack of fluctuations. Coast. Shelf Sci., 18(3): 459-483. eggs, larvae and juveniles in shallow surf or Leis, J.M. and B.M. Carson-Ewart – 2000. The Larvae of Indo- Pacific Coastal Fishes: an identification guide to marine fish nearshore plankton catches (Lasiak, 1983, 1984; larvae. Brill, Leiden. Strydom, 2003; Watt-Pringle and Strydom, 2003) Leis, J.M. and T. Trnski. – 2000. Chapter 118 Soleidae (Soles). In: J.M. Leis and B.M. Carson-Ewart (eds.), The Larvae of Indo- and the lack of larval fish research in offshore waters Pacific Coastal Fishes: an identification guide to marine fish of South Africa. Although there is no evidence to larvae. Brill, Leiden. Neira, F.J., Miskiewicz, A.G. and T. Trnski. – 1998. Larvae of tem- suggest a spawning migration given the prevalence perate Australian fishes. Laboratory Guide for larval fish iden- of mature females intertidally, it is not unlikely tification. University of Western Australia Press, Nedlands. Ochiai, A. – 1966. Studies on the comparative morphology and among flatfish, as Dagang et al. (1992) and ecology of the Japanese soles. Spec. Rep. Mar. Biol. Inst. Kyoto Shuozeng (1995) showed this to be the case for most Univ., 3: 1-97. Olivar, M.P. and J.M. Fortuño. – 1991. Guide to ichthyoplankton of flatfish species in the Yellow Sea, China. Further the southeast Atlantic (Benguela Current Region). Sci. Mar., research is required on soleid spawning strategies 55(1): 1-383. O’Toole, M.J. – 1977. Development and distributional ecology of off temperate South Africa. the larvae of the West Coast Sole Austroglossus microlepis. Fish. Bull. S. Afr., 9: 32-45. Russel, F.S. – 1976. The eggs and planktonic stages of British marine fishes. Academic Press, London. ACKNOWLEDGEMENTS Shuozeng, D. – 1995. Life history cycles of flatfish species in the Bohai Sea, China. Neth. J. Sea Res., 34(1-3): 195-210. Smith, M.M. and P.C. Heemstra. – 1986. Smiths’ Sea Fishes. The authors would like to thank the National Southern Book Publishers, Johannesburg. Strydom, N.A. – 2003. Occurrence of larval and early juvenile fish- Research Foundation, South Africa and DAAD, es in the surf zone adjacent to two intermittently open estuaries, Germany for funding this research. 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SCI. MAR., 71(3), September 2007, 421-428. ISSN: 0214-8358